Many arrangements exist in the prior art for applying glue to sheet material. For example, there are many paper converting and packaging operations which call for the application of adhesive to either the product itself or to bands or other wraps employed in the packaging of the products. In the former category, it is well known to apply glue to the tail end of a wound web, such as a tissue or towel roll, to secure the tail in position relative to the rest of the product. Insofar as packaging is concerned, bands of paper or other sheet material are often utilized to secure together a bundle of products, such as a stack of paper towels or napkins. The embodiment of the invention disclosed herein has application to wrap bands; however, as noted above, the invention has application in a wide variety of operational environments wherein glue is applied to sheet material.
Adhesive is primarily conventionally applied by either glue applicator wheels, brushes, or through the use of glue jets or nozzles which direct the adhesive to the desired location. These prior art approaches have a number of disadvantages. For example, glue applicator equipment is often relatively complex and expensive. Furthermore, glue applicator equipment employing either glue wheels, brushes or glue jets can become clogged and even inoperable over time, particularly when the adhesive has time to harden. Also, some approaches have the additional drawback of wasting glue. Use of adhesive applicator nozzles requires high operating adhesive pressures with attendant problems.
A search of the prior art located the following U.S. Pat. Nos.: 4,963,223, issued Oct. 16, 1990, No. 4,026,752, issued May 31, 1977, No. 2,361,795, issued Oct. 31, 1944, No. 4,897,145, issued Jan. 30, 1990, No. 3,761,300, Sep. 25, 1973, No. 4,878,981, issued Nov. 7, 1989, No. 3,532,573, issued Oct. 6, 1970, No. 4,502,912, issued Mar. 5, 1985, No. 3,505,150, issued Apr. 7, 1970, No. 4,370,193, issued Jan. 25, 1983, and No. 3,470,052, issued Sep. 30, 1969.
The above-identified patents are believed to be representative of the types of arrangements employed to apply glue to sheet material and related products.